Proposals to clear hundreds of acres of woodlands in Brookhaven and beyond to make way for large commercial solar arrays are pitting environmental and civic groups against one another.

As PSEG Long Island and LIPA expand green-energy programs, the latest fronts in the increasingly contentious battle have been in Mastic, where a 19.2-megawatt solar proposal last month went before the Brookhaven town planning board, and in Shoreham, where a potentially larger project is under consideration for the hundreds of acres of wooded land surrounding the Shoreham nuclear power plant.

National Grid, which owns the 800-acre Shoreham site, and partner NextEra Energy Resources would not confirm specifics of the plan, but have said they are examining a number of proposals to respond to a recent Long Island Power Authority request for proposals for green energy. Both stressed that no decisions have been made.

Some green-energy proponents say that while they’d prefer to avoid cutting down trees for solar arrays, they ultimately support the practice if it complies with local codes and hastens the transition away from fossil-fuel plants, which they say increase the growing threat of climate change. Long Island’s most visible environmental groups, including Renewable Energy Long Island and Citizens Campaign for the Environment, have supported a proposal for a 100-acre solar farm in Mastic that requires clearing some 60 wooded acres near the headwaters of the Forge River.

Last month Suffolk Leg. Kate Browning sent a letter to the developers to gauge interest in a possible sale to preserve the property. A spokesman said the developer is reviewing it.

Clear-cutting trees for solar is “not something you want to do if you can find a better place for it, but we don’t have a lot of time to debate this and study this,” said Gordian Raacke, executive director of Renewable Energy Long Island. “We have to keep moving on renewable energy.” Citizens Campaign called the Mastic project a “beneficial and prudent use of the land.”

But opponents say such considerations are shortsighted, failing to take into account the limited amount of undeveloped land on Long Island, and the importance of woodlands in reducing greenhouse gases and protecting groundwater.

Concerns about using farmland and other undeveloped space for large commercial solar arrays has been heightened since LIPA began issuing bid requests for renewable energy over the past four years. In 2014 it selected 11 large solar arrays in response to a request for proposals seeking up to 400 megawatts of green energy. Two of the 11 projects have dropped out.

LIPA and PSEG also have awarded dozens of smaller projects as part of a feed-in tariff program that pays businesses and developers a set fee for all the energy generated from the arrays under a long-term contract. A 60-acre sod farm in Shoreham that has already been converted to a solar farm evoked protests and a lawsuit from residents.

A separate plan by Suffolk County to work with developer SolarCity to put 13.5 megawatts of solar on some wooded county-owned parcels drew immediate objection from Brookhaven Supervisor Edward P. Romaine and some Suffolk legislators, who pushed for a study of the proposal. The plan won’t move forward until a new county task force mulls a range of uses for the land.

MaryAnn Johnston, president of the Affiliated Brookhaven Civic Organization, which has threatened to sue to block the Mastic solar farm, said she has broken off ties to environmental groups that are backing solar in woodlands. “It’s not renewable energy at any cost,” Johnston said.

If National Grid moves forward with a large array on land around the Shoreham nuclear site, it could present the biggest battle, Johnston and others say. The heavily wooded site contains high bluffs overlooking the Long Island Sound, wetlands and plentiful wildlife. “Obviously, it’s an area of concern,” said Sid Bail, president of the Wading River Civic Association.

Given the size of the site and the ample infrastructure to connect large amounts of energy to the LIPA grid from the old nuclear facility, it could accommodate 50 megawatts of solar power or more — eclipsing New York’s largest solar array at Brookhaven National Lab, which is 32 megawatts. A 50-megawatt array would require up to 300 acres of land.

Brookhaven Town has been the center of proposals for large solar arrays since the largest was completed at Brookhaven Lab in 2011. There, some 200 acres of woodlands were cleared to make way for the solar array, the largest East of the Mississippi. Opponents at the time decried the loss of some 40,000 trees for the project.

Shawn Nuzzo, president of Ecological Engineering of Long Island, a Stony Brook green-energy engineering firm, said brownfields and rooftops should be fully exploited before clear-cutting land for solar arrays. He’s overseeing a project that proposes a 6-megawatt solar array for a brownfield site in Kings Park.

“Rooftops, brownfields, these are the logical places to start with utility-scale solar, then if the need is still there, we can move onto these other areas,” Nuzzo said. “There are so many areas that we should start with first.”

With so much of the solar being proposed for Brookhaven along with several large projects that already are producing, Johnston and others have raised the question of whether there will be a glut of intermittent solar in the town.

Jeff Weir, a spokesman for PSEG, said it hasn’t been an issue — yet. “When we site projects, we make sure the reliability of the system is not degraded in any way,” he said. “We would never compromise reliability to accommodate any project.”